JP2017061639A - Urethane-based adhesive sheet, method for producing urethane-based adhesive sheet and method for controlling adhesive force of urethane-based adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a urethane-based adhesive sheet satisfying both proper adhesive force and reduction in residual glue.SOLUTION: There is provided a urethane-based adhesive sheet in which a substrate, a urethane-based adhesive layer, a release agent layer and a release substrate are arranged in this order, wherein the urethane-based adhesive layer and the release agent layer are arranged so as to be in direct contact with each other, wherein the release agent layer contains an addition reaction type silicone (excluding a silicone resin) and a silicone resin in a ratio of (the release agent layer):(the silicone resin)=100:0 to 99:1 (by mass) and the addition reaction type silicone is formed from a release agent composition containing at least one silicone compound having at least two crosslinking reactive groups.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a urethane-based pressure-sensitive adhesive sheet.

  Re-peelable pressure-sensitive adhesive sheets are used for glass protection in glass manufacturing processes for mobile devices such as smartphones. Moreover, such an adhesive sheet is used as a re-sticking sheet for office use, picture book use, educational use or children's plastic toy use that can be used repeatedly.

  The pressure-sensitive adhesive used for such a pressure-sensitive adhesive sheet is required to have an appropriate pressure-sensitive adhesive force and good removability. Conventionally, pressure-sensitive adhesives such as acrylic resins and rubber resins have been mainly used in such applications. However, these pressure-sensitive adhesives tend to cause adhesive residue on the adherend when peeled off from the adherend, the adhesive force tends to change with temperature, and the wettability to the adherend is insufficient. There has been a problem that air bubbles easily enter the interface with the adherend during bonding. For this reason, there is a demand for a pressure-sensitive adhesive that achieves both moderate adhesive strength, good removability and sufficient wettability to an adherend.

  Patent Document 1 discloses a re-sticking sheet in which one surface of an adhesive sheet substrate having an image has a urethane-based adhesive layer and is further protected by a release sheet. For such urethane-based pressure-sensitive adhesives, it is possible to achieve excellent productivity, moderate adhesive strength, and good re-stickability by selecting monomers, catalysts and reaction temperatures selected in the synthesis. It is disclosed.

JP 2000-256629 A

  However, the sheet for reattachment according to Patent Document 1 has been desired to be further improved from the viewpoint of achieving both appropriate adhesive strength and reduction of adhesive residue.

  Then, an object of this invention is to provide the urethane type adhesive sheet in which moderate adhesive force and reduction of the adhesive residue were compatible.

  In view of the above problems, the present inventors have intensively studied. As a result, it has been found that the above problem can be solved by setting the silicone compound used as the release agent layer of the urethane-based pressure-sensitive adhesive sheet to a predetermined composition, and the present invention has been completed.

  That is, in the present invention, the substrate, the urethane pressure-sensitive adhesive layer, the release agent layer, and the release substrate are arranged in this order, and the urethane pressure-sensitive adhesive layer and the release agent layer are arranged so as to be in direct contact with each other. The release agent layer contains addition reaction type silicone (excluding silicone resin) and silicone resin in a ratio of addition reaction type silicone: silicone resin = 100: 0 to 99: 1 (mass ratio), and The addition-reactive silicone is a urethane-based pressure-sensitive adhesive sheet formed from a release agent composition containing at least one silicone compound having at least two crosslinkable reactive groups.

  According to the present invention, it is possible to provide a urethane-based pressure-sensitive adhesive sheet that achieves both moderate pressure-sensitive adhesive strength and reduced adhesive residue.

It is a cross-sectional schematic diagram which shows one Embodiment of a urethane type adhesive sheet.

  In one embodiment of the present invention, a substrate, a urethane-based pressure-sensitive adhesive layer, a release agent layer, and a release substrate are arranged in this order, and the urethane-based pressure-sensitive adhesive layer and the release agent layer are arranged so as to be in direct contact with each other. The release agent layer contains addition reaction type silicone (excluding silicone resin) and silicone resin in a ratio of addition reaction type silicone: silicone resin = 100: 0 to 99: 1 (mass ratio); and The addition-reactive silicone is a urethane-based pressure-sensitive adhesive sheet formed from a release agent composition containing at least one silicone compound having at least two crosslinkable reactive groups. According to the urethane type adhesive sheet which concerns on one form of this invention which has such a structure, moderate adhesive force and reduction of adhesive residue can be made compatible.

  In the development of conventional urethane-based pressure-sensitive adhesive sheets, as disclosed in Patent Document 1, the selection of the type and amount of additives contained in the pressure-sensitive adhesive layer, as well as the formulation, structure and synthesis conditions of the urethane-based pressure-sensitive adhesive We have been trying to improve performance.

  On the other hand, unlike the conventional studies, the present inventors have attempted to solve the above problem by paying attention to the release agent layer used in the urethane-based pressure-sensitive adhesive sheet. As a result of intensive studies, the present inventors have found that the adhesive strength of the urethane-based pressure-sensitive adhesive layer varies greatly depending on the composition of the silicone compound used as the release agent, and also the degree of adhesive residue on the adherend during peeling. I found it very different. And surprisingly, by increasing the ratio of addition reaction type silicone (excluding silicone resin) contained in the release agent composition and lowering the ratio of silicone resin, it is in a good range as an adhesive sheet having removability. The present invention was completed by further finding out that adhesive strength was reduced and adhesive residue on the adherend during peeling was reduced.

  The inventors have increased the ratio of addition-reactive silicone contained in the release agent composition and reduced the ratio of silicone resin, thereby imparting appropriate adhesive strength to the urethane-based adhesive sheet and reducing adhesive residue. The mechanism is estimated as follows.

  Although the details are unknown as a main cause of excessive adhesive strength by including a high proportion of silicone resin in the silicone compound, it is presumed as follows.

  Silicone compounds that function as release agents include addition-reactive silicones and silicone resins. Here, the silicone resin is used to adjust the release force, but the silicone resin in the release agent layer diffuses from the release agent layer to the urethane-based pressure-sensitive adhesive layer arranged in direct contact with this layer. There is. At this time, the silicone resin functions to suppress the crosslinking reaction of the urethane-based pressure-sensitive adhesive layer. Therefore, the crosslinking reaction of the urethane-based pressure-sensitive adhesive layer sufficiently proceeds by increasing the ratio of the addition reaction type silicone contained in the release agent composition and decreasing the ratio of the silicone resin. As a result, it is possible to suppress the adhesive force from being excessive and to obtain an appropriate value. In addition, with regard to the reduction of adhesive residue, the urethane-based adhesive layer has slight adhesiveness with an appropriate adhesive force, so that the components derived from the adhesive layer remaining attached to the adherend at the time of peeling are reduced. Arise.

  Here, since the change in the adhesive force and the change in the behavior of the adhesive residue due to the ratio of the addition reaction type silicone and the silicone resin are not confirmed in the acrylic adhesive, the crosslinking reaction in the adhesive layer is not confirmed. The suppression is considered to be caused by a unique phenomenon that occurs between the urethane-based pressure-sensitive adhesive layer and the silicone resin.

  Therefore, the adhesive force and adhesive residue of urethane-based adhesive sheets are improved by increasing the ratio of addition-reactive silicone contained in the release agent composition and lowering the ratio of silicone resin, which cause such phenomena. It is thought that it is done.

  Note that the above mechanism is based on speculation, and its correctness does not affect the technical scope of the present invention.

In this specification, “X to Y” indicating a range means “X or more and Y or less”. Unless otherwise specified, the operation and physical properties are measured under conditions of room temperature (20 to 25 ° C.) / Relative humidity 40 to 50%.

  In the present specification, “acrylic” refers to “acrylic or methacrylic”.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios.

  Drawing 1 is a mimetic diagram of a section showing one embodiment of a urethane type pressure sensitive adhesive sheet. In FIG. 1, a urethane-based pressure-sensitive adhesive sheet 10 is configured by laminating a base material 11, a urethane-based pressure-sensitive adhesive layer 12, a release agent layer 13, and a release base material 14 in this order. Here, the urethane-based pressure-sensitive adhesive layer 12 and the release agent layer 13 are arranged so as to be in direct contact with each other and between the other members and outside the base material 11 and the release base material 14 optionally have other members. May be.

  Here, in this specification, a sheet includes a label and a seal.

  The urethane adhesive sheet preferably has an adhesive force to an adherend of 1 to 200 mN / 25 mm for use as a releasable adhesive sheet. Here, if it is 1 mN / 25 mm or more, better adhesion to the adherend can be imparted. Moreover, when it is 200 mN / 25 mm or less, it has more preferable adhesive force as a detachable adhesive sheet, and can reduce adhesive residue further. From the same viewpoint, it is more preferably 5 to 100 mN / 25 mm, further preferably 10 to 60 mN / 25 mm or less, and particularly preferably 20 to 40 mN / 25 mm or less.

In addition, the adhesive force to a to-be-adhered body sticks a urethane type adhesive layer to a SUS board, and measures 24 hours later according to JISZ0237: 2009 by a tensile tester at a test speed of 300 mm / min. More specifically, the adhesion to the adherend is a value measured by the following method;
The urethane-based pressure-sensitive adhesive sheet is allowed to stand in a 23 ° C. environment for 1 week. Then, it is left still in a standard environment (23 ° C., 50% RH) for one day, and the release agent layer is peeled off together with the release substrate, and the urethane pressure-sensitive adhesive layer surface is attached to the SUS plate (SUS # 600). After standing in a standard environment for 1 day, the adhesive strength is measured according to JIS Z0237: 2009. Specifically, the adhesive strength is measured by peeling off the sheet in a 180 ° direction at a test speed of 300 mm / min with a tensile tester. The numerical value is converted into a peeling force per sheet width of 25 mm (mN / 25 mm).

  Hereinafter, each structural member which comprises a urethane type adhesive sheet is demonstrated.

(Release agent layer)
In order to improve the peelability of the urethane-based pressure-sensitive adhesive layer, the release agent layer is provided on the release substrate as a configuration that is disposed so as to be in direct contact with the urethane-based pressure-sensitive adhesive layer. And a release agent layer is peeled from a urethane type adhesive sheet, when affixing with a peeling base material.

  The release agent layer is formed from the release agent composition. The release agent composition according to the present invention contains addition reaction type silicone and silicone resin in a ratio of addition reaction type silicone: silicone resin = 100: 0 to 99: 1 (mass ratio). When the silicone resin is contained in an amount exceeding 1% by mass with respect to the total mass of the addition reaction type silicone and the silicone resin, the adhesive strength is significantly increased and the adhesive residue is deteriorated. From the same viewpoint, it is preferably 100: 0 to 99.5: 0.5, more preferably 100: 0 to 99.8: 0.2, and even more preferably 100: 0.

  Although not an essential effect exhibited by the present invention, depending on the formulation and configuration of the urethane-based pressure-sensitive adhesive sheet, an additional effect is obtained that the smaller the ratio of the silicone resin, the less likely to cause winding displacement during winding. There may be cases. Also from this point, it is preferable that the ratio of the addition reaction type silicone and the silicone resin is within the above range.

  As described above, the addition reaction type silicone contains at least one silicone compound having at least two crosslinkable reactive groups, and is a mixture of an alkenyl group-containing organopolysiloxane and an organohydrogenpolysiloxane. Is particularly preferred.

  Examples of the alkenyl group in the alkenyl group-containing organopolysiloxane include a vinyl group and a hexenyl group. In order for the addition reaction type silicone to have a crosslinked structure, it is necessary to have at least two alkenyl groups in one molecule. From the viewpoint of the efficiency of the crosslinking reaction, it is preferable to have alkenyl groups at both ends.

  The alkenyl group-containing organopolysiloxane preferably contains a methyl group from the viewpoint of peelability.

  When the alkenyl group-containing organopolysiloxane contains a methyl group and a vinyl group, the ratio of the vinyl group to the methyl group is preferably 1 to 10 mol%. By making vinyl group content into the range of 1-10 mol% with respect to methyl group content, the intensity | strength of a cured film can be improved more and the peelability with respect to a urethane type adhesive layer is made into a more favorable range. be able to. From the same viewpoint, it is more preferably 2 to 7 mol%, and further preferably 3 to 5 mol%. In addition, about the ratio of a methyl group and a vinyl group, it can confirm by the gas chromatograph-mass spectrum (GC / MS) method.

  The organohydrogenpolysiloxane needs to have two or more SiH groups in one molecule in order for the addition reaction type silicone to take a crosslinked structure, and preferably has a methyl group from the viewpoint of peelability. .

  From the viewpoint of crosslinking efficiency, the organohydrogenpolysiloxane is preferably contained in an amount of 1 to 10 parts by mass with respect to 100 parts by mass of the alkenyl group-containing organopolysiloxane.

  The addition reaction type silicone preferably has a coating suitability and a viscosity of 25 ° C. in a solution having a solid content concentration of 30% by mass of 1000 to 20000 mPa · s, from the viewpoint of obtaining more appropriate peelability. It is more preferably 10,000 mPa · s, further preferably 3000 to 7000 mPa · s, and particularly preferably 4000 to 6000 mPa · s.

  As the silicone resin that can be contained in a predetermined amount or less in the release agent layer according to one embodiment of the present invention, one that contains 70% by mass or more of MQ resin is preferable.

The MQ resin is a silicone resin containing M units (R ₃ SiO _1/2 ) and Q units (SiO _4/2 ). Further, in addition to the M unit and the Q unit, a D unit (R ₂ SiO _2/2 ) or a T unit (RSiO _3/2 ) may be included. R represents a hydrogen atom, a hydroxyl group or an organic group, and is preferably a methyl group from the viewpoint of being easily dissolved in an organic solvent. The molar ratio of M unit to Q unit is preferably 0.5: 1 to 1: 1.

  The total content of the addition reaction type silicone and the silicone resin is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, and more preferably 90 to 100% with respect to the total mass of the release agent composition. More preferably, it is mass%.

  The release agent composition may contain any appropriate other component as long as the effects of the present invention are not impaired, in addition to the addition reaction type silicone and the silicone resin. For example, catalysts, reaction inhibitors, inorganic fillers, organic fillers, colorants (dyes and pigments, etc.), plasticizers, anti-aging agents, conductive agents, ultraviolet absorbers, antioxidants, light release agents and solvents. Can be mentioned. The release agent composition according to one embodiment of the present invention particularly preferably includes a silicone compound, a catalyst, and a solvent.

  The release agent composition preferably contains a catalyst. That is, the crosslinking reaction of the silicone compound in the curing of the release agent layer is preferably performed using a catalyst. The catalyst is not particularly limited, but a platinum-based catalyst is preferable, and chloroplatinic acid such as chloroplatinic acid and chloroplatinic acid, alcohol compounds of chloroplatinic acid, aldehyde compounds or chloroplatinic acid and More preferred are complexes with various olefins. 0.01-10 mass% is preferable with respect to the total mass of a releasing agent composition, and, as for the addition amount of a catalyst, it is more preferable that it is 0.2-2 mass%.

  The release agent composition preferably contains a solvent. Examples of the solvent include, but are not limited to, hydrocarbon solvents such as normal hexane, cyclohexane, and normal heptane; aromatic solvents such as toluene and xylene; ester solvents such as ethyl acetate and methyl acetate; Examples include ketone solvents such as acetone and methyl ethyl ketone (MEK); and organic solvents such as alcohol solvents such as methanol, ethanol, and butanol. In addition, an organic solvent may be used individually or in combination of 2 or more types.

  The release agent layer is preferably formed by applying a release agent composition on a release substrate.

As a coating method of the release agent composition at the time of forming the release agent layer, a coating method using a gravure coater, a bar coater or the like is appropriately used, and the adjusted release agent composition has a solid mass of 0.1 to 2. 0 g / ^{m 2,} preferably be applied so as to approximately 0.5 to 1.2 g / ^{m 2,} provided a release agent layer by curing.

  The curing method is preferably thermosetting in order to advance the addition reaction. Although it does not specifically limit as hardening temperature, It is preferable that it is 80 to 140 degreeC. When it is 80 ° C. or higher, heating for a long time is not required for sufficient curing, and more excellent productivity can be obtained. Moreover, generation | occurrence | production of the wrinkle by a heat | fever can be reduced in a base material or a peeling base material as it is less than 140 degreeC. From the same viewpoint, the temperature is more preferably 80 ° C to 130 ° C, and further preferably 90 ° C to 130 ° C. The thermosetting time varies depending on the formulation of the release agent composition, and is not particularly limited, but is preferably 5 seconds to 20 minutes, more preferably 10 seconds to 10 minutes, More preferably, it is 20 seconds to 5 minutes, and particularly preferably 30 seconds to 2 minutes. Here, the release agent composition may be cured under only one curing condition, or may be cured through two or more identical or different curing conditions.

  Although it does not specifically limit as thickness of a release agent layer, It is preferable that it is 0.1-2 micrometers, and it is preferable that it is 0.5-1.2 micrometers.

(Urethane adhesive layer)
A urethane type adhesive layer is obtained by apply | coating a polyurethane type adhesive composition, drying, and bridge | crosslinking.

  The polyurethane pressure-sensitive adhesive composition preferably contains a urethane prepolymer, a polyfunctional isocyanate compound, a catalyst and a solvent.

  The urethane prepolymer is preferably polymerized by charging a polyester polyol and / or a polyether polyol, a polyfunctional isocyanate compound, a catalyst and a solvent all at once and heating.

  Examples of polyester polyols include those obtained by reacting acid components such as adipic acid and terephthalic acid with glycols such as 3-methyl-1,5-pentanediol and propylene glycol. The molecular weight of the polyester polyol is preferably 1,000 to 6,000. When the number average molecular weight is 1,000 or more, gelling of the urethane prepolymer can be further suppressed by reducing the reactivity. When the number average molecular weight is 6,000 or less, the cohesive force of the urethane prepolymer increases, and as a result, the adhesive residue of the polyurethane pressure-sensitive adhesive can be further suppressed.

  Examples of the polyether polyol include polyethylene glycol (polyethylene oxide), glycerin-propylene oxide / ethylene oxide adduct, and the like.

  Examples of the polyfunctional isocyanate compound include hexamethylene diisocyanate, 4,4′-diphenylmethane diisocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct, and the like.

  Examples of the catalyst include tin compounds such as dioctyltin dilaurate and dibutyltin dilaurate, and tertiary amine compounds such as triethylamine and triethylenediamine.

  Examples of the solvent include toluene, ethyl acetate, methyl ethyl ketone, and the like.

(Base material)
Although it does not specifically limit as a base material, For example, paper base materials, such as a craft paper and Japanese paper, a plastic film (thermoplastic resin film), a synthetic paper etc. are mentioned. Examples of the plastic film material (thermoplastic resin) include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), and the like. Olefin resin containing α-olefin as monomer component; Polyester resin such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT); Polyvinyl chloride (PVC); Vinyl acetate resin; Examples include polycarbonate (PC). These materials may be used alone or in combination of two or more.

Examples of the synthetic paper include polyester films and polypropylene films having fine voids. Among the above-mentioned substrates, examples of the base material include polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polypropylene (PP), and the like. Polyolefin films such as polymethylpentene (PMP), polycarbonate films (PC), and polyvinyl acetate films are preferred, polyester films and polyolefin films are more preferred, polyester films are more preferred, and polyethylene terephthalate (PET) films are particularly preferred.

  As the plastic film, any of an unstretched film and a stretched (uniaxially stretched or biaxially stretched) film can be used. The surface of the substrate on which the pressure-sensitive adhesive layer is provided may be subjected to a surface treatment such as application of a primer or corona discharge treatment.

  The thickness of the base material is preferably 10 to 100 μm, and more preferably 10 to 50 μm.

(Peeling substrate)
A peeling base material is a member which has a function which protects a urethane type adhesive layer and prevents the fall of adhesiveness. A release agent layer disposed so as to be in direct contact with the urethane-based pressure-sensitive adhesive layer is provided on the release substrate. And a peeling base material is peeled from a urethane type adhesive sheet, when affixing with a release agent layer.

  The release substrate is not particularly limited. For example, a paper substrate such as glassine paper or high-quality paper, a laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper substrates, and a plastic film ( Thermoplastic resin film). The laminated paper may be a laminate of a paper base material and a plastic film. Examples of the laminated thermoplastic resin or plastic film material (thermoplastic resin) include, for example, polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), ethylene-propylene copolymer, and ethylene-vinyl acetate. Olefin resins containing α-olefin as a monomer component such as copolymer (EVA); Polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT); Polyvinyl chloride (PVC) ); Vinyl acetate resin; Polycarbonate (PC); Polyphenylene sulfide (PPS); Amide resin such as polyamide (nylon) and wholly aromatic polyamide (aramid); Polyimide resin; Polyetheretherketone (PEEK) And the like. These materials may be used alone or in combination of two or more.

  Among these, as the release substrate, polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin films such as polyethylene (PE), polypropylene (PP), etc. are preferable, polyester films and polyolefin films, Or it is more preferable that it is the laminated paper which laminated | stacked the paper base material and these films.

  Here, in the urethane-based pressure-sensitive adhesive sheet according to one embodiment of the present invention, a polyolefin film or a paper base material and a polyolefin are used as a peeling base material because of excellent physical properties, low cost, and high productivity. More preferably, a laminated paper laminated with a film is used. In the present invention, a polyolefin film can be preferably used because the peeling force can be easily controlled to a practically suitable range. From the same viewpoint, a polyethylene film, a polypropylene film, or a laminated paper obtained by laminating these with a paper base material is particularly preferable, and a polypropylene (PP) film is most preferable.

  The thickness of the release substrate is preferably 10 to 400 μm.

(Other parts)
The urethane pressure-sensitive adhesive sheet according to one embodiment of the present invention is arranged so that the urethane-based pressure-sensitive adhesive layer and the release agent layer are in direct contact with each other. You may have the member.

(Method for producing urethane-based adhesive sheet)
Another embodiment of the present invention is a method for producing a urethane-based pressure-sensitive adhesive sheet according to one embodiment of the present invention.

As a method for producing a urethane-based pressure-sensitive adhesive sheet according to an embodiment of the present invention, for example,
The base material, urethane-based pressure-sensitive adhesive layer, release agent layer, and release base material are arranged in this order.
The urethane-based pressure-sensitive adhesive layer and the release agent layer are a method for producing a urethane-based pressure-sensitive adhesive sheet arranged so as to be in direct contact with each other,
The release agent layer contains addition reaction type silicone (excluding silicone resin) and silicone resin in a ratio of addition reaction type silicone: silicone resin = 100: 0 to 99: 1 (mass ratio), and addition reaction type silicone. Is formed by a step of curing a release agent composition containing at least one silicone compound having at least two crosslinkable reactive groups.
The manufacturing method of a urethane type adhesive sheet is mentioned.

  As described in the description of the release layer and the urethane-based pressure-sensitive adhesive layer, the urethane-based pressure-sensitive adhesive sheet according to one embodiment of the present invention is not particularly limited as described above, but the following method 1 and 2 is preferable.

Method 1;
An addition reaction type silicone (excluding silicone resin) and a silicone resin are contained on a release substrate in a ratio of addition reaction type silicone: silicone resin = 100: 0 to 99: 1 (mass ratio), and the addition reaction type Applying a release agent composition containing at least one silicone compound having at least two crosslinkable reactive groups and then curing to form a release agent layer;
After directly applying the urethane-based pressure-sensitive adhesive composition on the release agent layer, drying and forming a urethane-based pressure-sensitive adhesive layer;
Joining the base material on the urethane-based pressure-sensitive adhesive layer;
A process for aging a laminate comprising a substrate, a urethane-based pressure-sensitive adhesive layer, a release agent layer and a release substrate, and a method for producing a urethane-based pressure-sensitive adhesive sheet.

Method 2;
After applying a urethane-based pressure-sensitive adhesive composition on a substrate, drying and forming a urethane-based pressure-sensitive adhesive layer;
An addition reaction type silicone (excluding silicone resin) and a silicone resin are contained in a ratio of addition reaction type silicone: silicone resin = 100: 0 to 99: 1 (mass ratio) on the release agent layer, and the addition reaction type Applying a release agent composition containing at least one silicone compound having at least two crosslinkable reactive groups and then curing to form a release agent layer;
On the laminate including the base material and the urethane pressure-sensitive adhesive layer, the step of joining the laminate including the release base material and the release agent layer so that the urethane pressure-sensitive adhesive layer and the release agent layer are in direct contact;
A process for aging a laminate comprising a substrate, a urethane-based pressure-sensitive adhesive layer, a release agent layer and a release substrate, and a method for producing a urethane-based pressure-sensitive adhesive sheet.

  In the method 1, since the other layer is directly formed on one of the release agent layer and the urethane-based pressure-sensitive adhesive layer, the release agent layer and the layer are bonded to each other after drying. The time during which the interface of the urethane-based pressure-sensitive adhesive layer is in contact is longer. As a result, in the conventional release agent layer having a high silicone resin content, the crosslinking reaction of the urethane-based pressure-sensitive adhesive layer is suppressed, and an appropriate adhesive force cannot be obtained, and the occurrence of adhesive residue occurs. On the other hand, in the method for producing a urethane-based pressure-sensitive adhesive sheet according to an embodiment of the present invention, an appropriate pressure-sensitive adhesive can be obtained even by a manufacturing method in which the interface between the release agent layer and the urethane-based pressure-sensitive adhesive layer is longer. A urethane-based pressure-sensitive adhesive sheet in which generation of force and adhesive residue is suppressed can be produced. This reason is presumed to be an effect obtained because the content of the silicone resin in the release agent composition is small as described in the description of the urethane pressure-sensitive adhesive sheet. From this, the manufacturing method of the urethane type adhesive sheet which concerns on one form of this invention can expand the width | variety of the manufacturing method of a urethane type adhesive sheet, and can improve productivity more.

  Here, Method 1 is preferable as a method for producing a urethane-based pressure-sensitive adhesive sheet used as a re-sticking sheet with an image attached to the sheet. Here, examples of the use of the re-sticking sheet include office use, picture book use, educational use, and children's plastic toy use that can be used repeatedly. Method 2 is particularly preferable as a method for producing a urethane pressure-sensitive adhesive sheet used for glass protection in a glass production process for mobile devices such as smartphones.

  The urethane pressure-sensitive adhesive layer and the release agent layer are formed so as to be in direct contact with each other, but an optional member manufacturing process is further provided so as to be disposed between other members and outside the substrate and the release substrate. Also good.

  The aging treatment is performed in order to balance physical properties of the urethane-based pressure-sensitive adhesive layer such as adhesive strength. As conditions for the aging treatment, the temperature is usually 0 to 150 ° C., preferably 10 to 100 ° C., particularly preferably 20 to 80 ° C., and the time is usually within 30 days, preferably within 14 days, particularly preferably 7 days. Specifically, for example, the reaction can be performed under conditions of, for example, 23 ° C. for 3 to 10 days, 40 ° C. for 1 to 7 days, and the like.

  In addition, the detail of each member which comprises the urethane type adhesive sheet used in this manufacturing method or manufactured is the same as that of the above-mentioned.

(Adhesive strength control method of urethane adhesive sheet)
Another embodiment of the present invention is a method for controlling the adhesive strength of a urethane-based adhesive sheet.

That is, the base material, the urethane-based pressure-sensitive adhesive layer, the release agent layer formed from the release agent composition, and the release base material are arranged in this order, and the urethane-based pressure-sensitive adhesive layer and the release agent layer are in direct contact with each other. In the urethane-based adhesive sheet that is arranged,
The ratio of addition reaction type silicone (excluding silicone resin) and silicone resin contained in the release agent composition is addition reaction type silicone: silicone resin = 100: 0 to 99: 1 (mass ratio), and the addition reaction This is a method for controlling the adhesive strength of a urethane-based pressure-sensitive adhesive sheet, in which a desired type of adhesive strength is obtained when the type silicone contains at least one silicone compound having at least two crosslinkable reactive groups.

  According to the pressure-sensitive adhesive strength control method for such a urethane pressure-sensitive adhesive sheet, the crosslinking control effect of the urethane-based pressure-sensitive adhesive layer by the formulation of the release agent layer can be favorably obtained.

  In addition, the detail of each member which comprises a urethane type adhesive sheet and its manufacturing method is the same as the above-mentioned thing.

(Use)
Although the use of the urethane type adhesive sheet which concerns on one form of this invention is not specifically limited, It is preferable that it is a glass protection use in the glass manufacturing process of mobile apparatus uses, such as a smart phone. When the urethane adhesive sheet according to one embodiment of the present invention is used as a re-pasteable sheet with an image attached to the sheet, it can be used repeatedly for office use, picture book use, educational use or children's plastic toy. It is preferable to be used.

The effects of the present invention will be described using the following examples and comparative examples. "Part" in the examples
Alternatively, “%” may be used, but “part by mass” or “mass%” is expressed unless otherwise specified.

[Production of urethane-based adhesive sheet]
Example 1
First, a release substrate was prepared in which a polyethylene film having a thickness of 20 μm was laminated on high-quality paper having a basis weight of 100 g / m ² .

  Next, an organic compound having a viscosity of 5000 mPa · s at 25 ° C. containing an addition-reactive silicone having a vinyl group content of 4 mol% based on the methyl group content of the base polymer and a solid content concentration of 30% by mass. A solvent solution was prepared. Further, a platinum-based catalyst as a catalyst was added to this solution so as to have a solid content concentration of 1% by mass. The addition reaction type silicone contains an organopolysiloxane having at least two vinyl groups as a crosslinkable reactive group and an organohydrogenpolysiloxane. Thereafter, toluene as a diluent solvent was added to the solution so as to have a solid content concentration of 10% by mass, and stirring was performed for 20 minutes to prepare a release agent composition.

The prepared release agent composition was applied onto the release substrate with a gravure coater so that the solid content was 0.8 g / m ² and the thickness after curing was 0.9 μm. It was dried and cured for a minute to form a release agent layer.

  Next, a urethane prepolymer solution and a polyfunctional isocyanate compound (trade name: Coronate HX, manufactured by Tosoh Corporation) are mixed at a solid content ratio of 100: 10 and stirred with a disper to obtain a polyurethane-based pressure-sensitive adhesive composition. It was.

  The solution of the urethane prepolymer is 100 parts by mass of a polyester polyol (trade name: Kuraray polyol P-1010, manufactured by Kuraray Co., Ltd.), 15 parts by mass of a polyfunctional isocyanate compound (trade name: Coronate HX, manufactured by Tosoh Corporation), a catalyst. (Dioctyltin dilaurate) was obtained by reacting 0.1 part by mass and 170 parts by mass of a solvent (toluene) at 90 ° C. for 4 hours.

  Then, the obtained polyurethane adhesive composition was applied on a release agent layer so that the thickness after curing with a knife coater was 15 μm, and dried at 130 ° C. for 3 minutes to obtain a urethane adhesive layer. Formed.

  Furthermore, after joining the base material which consists of a polyester film (50 micrometers in thickness) to the surface of a urethane type adhesive layer, aging was performed for 7 days at normal temperature, and the urethane type adhesive sheet 1 was produced.

(Comparative Example 1)
In Example 1, the urethane type adhesive sheet 2 was produced similarly except having changed the releasing agent composition as follows.

  An addition reaction type silicone having a vinyl content of the base polymer of 4 mol% with respect to the methyl group content is a solid content concentration of 28.5% by mass, an MQ resin (M unit and Q unit) of silicone resin. An organic solvent solution containing a molar ratio of 0.7: 1) and a solid content concentration of 1.5% by mass was prepared. Furthermore, a platinum-based catalyst as a catalyst was added to this solution so as to have a solid concentration of 1% by mass. The addition reaction type silicone contains an organopolysiloxane having at least two vinyl groups as a crosslinkable reactive group and an organohydrogenpolysiloxane. Thereafter, toluene as a diluent solvent was added to the solution so as to have a solid content concentration of 10% by mass, and stirring was performed for 20 minutes to prepare a release agent composition.

  Table 1 shows the mass ratio of the addition reaction type silicone and the silicone resin contained in the release agent composition layer forming the release agent layer in these urethane-based pressure-sensitive adhesive sheets.

[Performance evaluation]
(Adhesive force)
The urethane-based pressure-sensitive adhesive sheet was allowed to stand for 1 week in a 23 ° C. environment. Then, it was left still in a standard environment (23 ° C., 50% RH) for one day, the release agent layer was peeled off together with the release substrate, and the urethane-based pressure-sensitive adhesive layer surface was attached to a SUS plate (SUS # 600). After standing in a standard environment for 1 day, the adhesive strength was measured according to JIS Z0237: 2009. Specifically, the adhesive strength was measured by peeling off the sheet in a 180 ° direction at a test speed of 300 mm / min with a tensile tester. The numerical value is converted into a peeling force per sheet width of 25 mm (mN / 25 mm). As the measurement value, the above measurement was repeated twice, and the average value of the obtained values was used. These results are shown in Table 1.

(Adhesive residue)
Adhesive residue evaluation test A release member comprising a release agent layer and a release substrate from a urethane adhesive sheet cut to a size of 3 cm x 5 cm using a float glass plate of 7 cm x 15 cm and a thickness of 2 mm as a test piece (adhered body) Was peeled off, and the urethane pressure-sensitive adhesive layer surface of the sheet was affixed so as not to contain bubbles, and a moist heat acceleration test was conducted for 300 hours in an environment of 60 ° C. and 95% RH. Thereafter, the sheet was left at room temperature for 1 hour, and then the sheet was peeled off, and the surface of the adherend was observed with a digital microscope to examine the presence or absence of adhesive residue. Evaluation of adhesive residue was performed according to the following criteria.

○: The ratio of the adhesive residue in 1 cm ² is less than 5%:
Δ: The ratio of the adhesive residue in 1 cm ² is 5% to less than 30%:
×: The ratio of the remaining adhesive in 1 cm ² is 30% or more:
These results are shown in Table 1.

  From the above results, the release agent contains addition reaction type silicone (excluding silicone resin) and silicone resin in a ratio of addition reaction type silicone: silicone resin = 100: 0 to 99: 1 (mass ratio), and When the addition-reactive silicone contains at least one silicone compound having at least two crosslinkable reactive groups, it was confirmed that the addition-reactive silicone had a suitable adhesive force as an adhesive sheet and no adhesive residue was generated.

10 Urethane adhesive sheet,
11 substrate,
12 Urethane adhesive layer,
13 release agent layer,
14 Peeling substrate.

Claims (7)

The base material, urethane-based pressure-sensitive adhesive layer, release agent layer, and release base material are arranged in this order.
The urethane pressure-sensitive adhesive layer and the release agent layer are arranged so as to be in direct contact with each other,
The release agent layer contains addition reaction type silicone (excluding silicone resin) and silicone resin in a ratio of addition reaction type silicone: silicone resin = 100: 0 to 99: 1 (mass ratio), and the addition reaction The type silicone is formed from a release agent composition containing at least one silicone compound having at least two crosslinkable reactive groups.
Urethane adhesive sheet.   The urethane pressure-sensitive adhesive sheet according to claim 1, wherein the addition reaction type silicone is a mixture of an alkenyl group-containing organopolysiloxane and an organohydrogenpolysiloxane.   The urethane pressure-sensitive adhesive layer was affixed to a SUS plate, and the adhesive force measured at a test speed of 300 mm / min in a 180 ° direction with a tensile tester in accordance with JIS Z0237: 2009 after 24 hours was 1 to 200 mN / 25 mm. The urethane-type adhesive sheet of Claim 1 or 2.   The urethane-based pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the release substrate is a polyethylene film, a polypropylene film, or a laminated paper obtained by laminating these with a paper substrate. The base material, urethane-based pressure-sensitive adhesive layer, release agent layer, and release base material are arranged in this order.
The urethane-based pressure-sensitive adhesive layer and the release agent layer are a method for producing a urethane-based pressure-sensitive adhesive sheet arranged so as to be in direct contact with each other,
The release agent layer contains addition reaction type silicone (excluding silicone resin) and silicone resin in a ratio of addition reaction type silicone: silicone resin = 100: 0 to 99: 1 (mass ratio), and the addition reaction The mold silicone is formed by curing a release agent composition containing at least one silicone compound having at least two crosslinkable reactive groups,
A method for producing a urethane-based pressure-sensitive adhesive sheet. An addition reaction type silicone (excluding silicone resin) and a silicone resin are contained on the release substrate in a ratio of addition reaction type silicone: silicone resin = 100: 0 to 99: 1 (mass ratio), and the addition reaction A step of applying a release agent composition containing at least one silicone compound having at least two crosslinkable reactive groups, and then curing to form a release agent layer;
After directly applying the urethane pressure-sensitive adhesive composition on the release agent layer, drying and forming the urethane pressure-sensitive adhesive layer;
Joining the base material on the urethane-based pressure-sensitive adhesive layer;
A process for producing a urethane-based pressure-sensitive adhesive sheet according to claim 5, comprising a step of aging a laminate comprising the substrate, the urethane-based pressure-sensitive adhesive layer, the release agent layer, and the release substrate. The base material, the urethane-based pressure-sensitive adhesive layer, the release agent layer formed from the release agent composition, and the release base material are arranged in this order, and the urethane-based pressure-sensitive adhesive layer and the release agent layer are in direct contact with each other. In the urethane-based adhesive sheet that is arranged,
The ratio of addition reaction type silicone (excluding silicone resin) and silicone resin contained in the release agent composition is addition reaction type silicone: silicone resin = 100: 0 to 99: 1 (mass ratio), and the addition A method for controlling the adhesive strength of a urethane-based pressure-sensitive adhesive sheet, wherein the reactive silicone contains at least one silicone compound having at least two crosslinkable reactive groups to obtain a desired adhesive strength.